Pulpstone



Dec. 30, A1947. N. F. HOLTER 2,433,814

Filed May 18, 1946 NORMAN F. HoLTz-:R

Patented Dec. 30,1947

pplieiiqllllay 18, 194.6, 1Serial 91 67,038.8

vFIhe invention 'relates to pulpstones, and with regard `to its frnore'specic features to pulpst'ones 'fcrgrinding'long'log-S.

One object of the invention is to provide a long pulpstene fer exemple fiflebfef ght'ft j@ .length (length here meaning the airialdimension). vAnother' object `is to provide la strong pulpstone of considerable length. 'Another object is to provide a pulpstone and mount of the size and weight necessary to grind "longlogs', of

capable of long continued anddependable operation. Another object o f nthe'invention isto provide a construction for a long 9111115150111@ ,Which is economical ,to manufacture. Another object 4 claims. (c1. 5lzaait .0 simple and practical constructionand which lis is AtoprovideI driving means'for a pulpstone which is capable of absorbing a greater amount of horse power than conventionalr'driving means.

Another object 0f .the .im/enti@ .is t? Provide a long pulpstone capable of being used in 4high stresses and pressures at the flanges and upon the' concrete center. v(fither objects will be in A.partpbvions or in Vpart pointedout hereinafter.

{I he invention laccordingly consists in the lfea,-

lProduction grinding withoutdeveloping excessive 1 tures of construction, combinations ofelements and arrangements ofvparts, as will beeXempl-ifled ,inthe structure A,tobe hereinafter described, and

the scope of the application of which willbe indicated in the following claims.

In the accompanying drawings, in which lis .shown one ofthe various possible embodiments ,ofthe mechanical yfeatures ofthis invention,

H Figure 1 isan axialsectional view oionehalf of a pulpstone constructed in accordance with .the invention, together with the driving flange yand the driving shaft. I

.Figure 2 is an end elevation of a portion of the pulpstone, with part `thereof shown in cross section, all on a larger scale than-Figure 1.

Asconducivetoa clearer understanding of the present invention it is noted thatpulps'tone's are customarily driven by anges on right'and left .hand threads oriwthe driving shaft; such constru'ctc'n' 'compressing the ilanges' against' the ends o'f the pulp'stonethuslprovidingpressurefor frictional driving. "The pressure'is a'funfctio of the :power factor as will belreadily understood.

'Pulpstones now used are common-1y nolmor'e than 'vef'feet 'in'axial dimension,y usually less. :In-such stones the power 'factor isnot great enoughl` to setup v'pressures which' could crush the stones"- VAccording to the present invention; however, it

.l isfcontemplated that'st'onfes eight -and" evenV nine 'l 'feet long 'will benconstructed. l ,If the jiflan'gefrictherefore, fo

tion ,were used to do the driving very large pressures! uidefcjreated. :afl-infatuation nage-r.- v-a mrecverybyuie differentialifexpansion of lfa'ssuriies'l serious proianaievbdne .giacevaA H m'theaajacent 10i-oak.'V 1

he blocks I9 are'tli'enfired in la kiln and the shape i'fhus?y becomes permanent and-th material ifs-thereby converted-to?witried-bondedabrasive materia-1; I provide fgfquanuty for bolts-2o havfing heads `2|vvithgrooves12'2; I lfurther'prclivide nach "groove n is adjacent to amnesponqmg 12o abutting the -fheads 2.2191111 fthenf piacewme `washers 24 against'the ends v'-oithe s1`eev'es'f25,

place-t'he lnutsupontheouter threaded-ends 26 2p and llthe--s'pa'ce with 1i-suitableselfsetting cement 3U such-a`s-`a miX-tureof/Portland cement and* ir -ilings. This' hasf excellent holding povver.v -E'ach block I thu's-has four bolts 220 projecting therefrom, eachbolt' being encased by'a Isleeve 25'fand`having attached toit Aa washer 24.

v:nach ceniza isnnuer initial tension such thaleia considerable for'cefis needed to'movethe head 2-I 'away from the Jwasher "24 by even averyslight distance. Each bolt '2011s securely locked toit-s `segment! I0 byreason'fof the fact that theoement 11 vir'iterlo c'lfzs'vvitlfrthe grooves I 6 in the blockI and also interlocks with the grc'ovesj 22 the headjZl,

I now arrange the blocks ill in rows to form a hollow cylinder of outside diameter equal to that of the finished pulpstone. Between the blocks I place suitable filler material 32 such as that described in U. S. Patent No. 2,054,771. The blocks are clamped together and the whole assembly is placed in an oven to bake the material 32. Inside this hollow cylinder after it is removed from the oven I place cages formed of hoops of steel 33 spaced apart axially by metal clips, not shown. Preferably there are a plurality of cages made of hoops, for example three as shown, the hoops of one cage being of a different diameter from the hoops of another cage. The cages serve to reinforce the stone against centrifugal and other radial forces.

According to this invention I provide a hollow cylindrical metal drum 35 having enlarged end portions 36 bounded by conical surfaces 31 on the inside, and radial plane annular faces 38. Screwed into the drum 35 are a plurality of bolts 39 which project radially outward. I place the drum 35 inside the cages of hoops 33 and coaxial with the hollow cylinder of blocks l@ and the cages. The drum 35 rests upon a mold bottom plate, not shown, which does not form part of the final pulpstone. A mixture of concrete forming material such as Portland cement, sand and trap rock is now poured inside the cylinder of blocks it! and allowed to set. The surface of the upper end is shaped to be the same as that of the lower end before the concrete has set. The clamp and the mold bottom plate are then removed and the stone is trued, dressed and sided. The pulpstone per se is now finished.

The pulpstone will usually be mounted upon a drive shaft d@ which has large keyways iii. I provide large flanges :l2 which are bored to fit over the shaft dil and have large internal keyways i3 to t opposite the keyways lll upon the shaft QQ. The flanges 5:2 are identical. They have radial plane annular faces ill to nt against the radial plane annular faces 38 of the drum S5. Bolts i5 with locknuts it and washers il extend through holes d8 in the flanges i2 and into tapped holes d in the faces 33 of the drum S thus holding the pulpstone upon the shaft di). Heavy wedge keys 5i) nt into the keyways il upon the shaft iii and the keyways 3 in the flanges li and securely lock the pulpstone to the shaft [iii so that it may be driven. Bolts 5l having lock nuts 52 extend through holes 53 in extensions Sill in the heads of the keys t and into tapped holes 55 in the flanges l2 to hold the keys 5% wedged securely in place.

In order to assemble the pulpstone with the flanges l2 and keys 50 on the shaft liti, the shaft is dismounted from its journal at one end, the flange i2 farthest from that end is placed over its keyways fll, the pulpstone is placed upon the shaft and the other flange l2 is placed over its keyways fil. The bolts 45 are inserted, screwed in and tightened with their locknuts lili, on both ends of the pulpstone locking the stone to its flanges Q2. Then the keys 5i! are inserted and driven into their keyways fil and 63 to lock the pulpstone and flanges i2 to the shaft iii). The bolts iii are inserted and tightened to hold the keys 5t securely in place. Then the journal can be replaced and the stone is ready to operate upon its shaft lid.

In conventional stones which are usually not more than four or five feet in length, the screw thread drive is used whereby the end flanges are screwed against the stone by right and left hand UJI screw threads upon the shaft. The stone is driven through the friction created by the flanges against its ends as they are compressed against it caused by their tending to be driven together along the opposite screw threads as the shaft drives them. This sets up compressional and ltensional stresses in the concrete at the flanges,

which however are not too greatin a stone of short axial length, and the expansion differential between the concrete and the steel shaft is not a serious problem in the short stone. However, in a stone of long axial length such as eight or nine feet as embodied in the present invention, the proportionally greater horsepower absorption by the stone through its driving means precludes the frictional drive method by flanges which are driven upon the shaft by opposite screw threads. The concrete could not withstand the greater conipressional and tensional forces caused by the compressive thrust of the flanges driven against it by the greater power through a screw thread drive and the expansion differential between the steel shaft and the concrete in a long stone would create a serious problem.

Furthermore in former construction the flanges would frequently get so tight they would freeze to the shaft, whereas by this method the keys will get no tighter than they are originally set, and dismounting of a stone for repairs does not become a problem in spite of greater power absorption necessary to drive the longer stone. Also the ratcheting action due to slippage of the anges where the drive is frictional is eliminated by the positive drive provided by the invention. Power is absorbed by the drum 35 throughout the entire length of the stone, and this eliminates pressures which could crush the stone as well as acute stresses at the ends of the stone.

In the preferred embodiment of a stone constructed according to this invention, I provide abrasive end plates 63 of the same material as the blocks l@ which lie yon the ends of the concrete abutting the blocks l0 in a radial plane. These abrasive plates {Si} protect the concrete from excessive wear caused by the presence of grinding water with abrasive particles therein and from wood splinters carrying abrasive which become lodged between the end of the stone and the frame of the pulp grinder. The plates iii! on one end are placed upon the bottom mold plate before the concrete is poured and they are set into the concrete on the top end before it sets.-

The foregoing plates 60 are described in greater detail in U. S. Patent No. 2,205,296 to Carl L. Leafe.

It will thus be seen that there has been provided by this invention a pulpstone in which the various objects hereinbefore set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might -be made in the embodi ment set forth it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a pulpstone, a plurality of blocks of bonded abrasive material, said blocks being arranged to form a hollow body of revolution, a hollow concrete core inside of said body of revolution, bolts embedded in said blocks and in said core attaching said blocks to said hollow concrete core, a hollow metal drum inside of said hollow concrete core having enlarged end por- 5' tions, the outer enlarged end portions of said hollow metal drum being bored and tapped for the reception of driving bolts.

2. In a pulpstone as claimed in claim 1, a combination with the parts and features therein specified, of a plurality of metal members attached to said drum and extending radially into said hollow concrete core to drive said core from said drum.

3. A pulpstone assembly comprising a driving shaft having keyways, a pair of annular metal flanges tting said shaft and having internal keyways matching the keyways on the driving shaft, a hollow cylindrical metal drum having enlarged end portions tted to the flanges, bolts securing the anges to the end portions of the metal drum, keys in the keyways of the shaft and in the internal keyways locking the anges to the shaft, a concrete core cast around the metal material outside of and in contact with said concrete core said blocks being arranged to forni REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 667,304 Feix Feb. 5, 1901 1,684,770 Larsson Sept. 18, 1928 1,979,074 Larsson Oct. 30, 1934 Rickard Jan. 4, 1938 

